Sweyn Forkbeard

Sweyn Forkbeard (960-1014) was the king of Denmark from 986 to 1014 (succeeding Harald Bluetooth and preceding Harald II of Denmark), King of Norway from 1000 to 1014 (succeeding Olav Tryggvason and preceding Olaf II of Norway), and King of England from 1013 to 1014 (succeeding Aethelred the Unready and preceding Aethelred). His son Canute would go on to create a Nordic empire after his death.

Biography
Sweyn Forkbeard was born in 960 to King Harald Bluetooth of Denmark and Tove of the Obotrites, and he was from the Norse Christian House of Knytling. He succeeded his father as king of Denmark and Norway on his death in 986, but in 995 he lost Norway to Olav Tryggvason, who became a major Norse king. Sweyn was one of the nobles who fought Olav at the Battle of Svold in 1000, where Olav drowned himself as his navy was defeated. Sweyn became the new king of Norway afterwards, and in 1013 he embarked on an ambitious invasion of England, led by Aethelred the Unready (who massacred Danish settlers in 1002). From 1002 to 1005, 1006 to 1007, and 1009 to 1012 he tried to avenge the St. Brice's Day Massacre, and in 1013 he forced Aethelred to flee to Normandy as he became the new king of England. Sweyn lost England when Aethelred returned in 1014, and his son Canute would retake England by storm in 1016 and form a Nordic empire.